Simulation Method and Analysis of Spring Failure in Press-Pack IGBT Devices Based on Electro-Thermal Co-Simulation

Spring failure is one of the main failure modes of press-pack IGBT devices, which is mainly manifested in the stress relaxation of the internal spring of the gate thimble, which affects the electrical contact and switching ability of the chip. In this paper, a spring failure simulation method for press-pack IGBT devices based on electro-thermal co-simulation is proposed. Firstly, a single-chip finite element model of press-pack IGBT device considering gate pin is established, the simulated thermal field distribution is obtained. Secondly, based on the characteristics of the electrical end of the chip, the power loss model of the chip and the circuit model that can reflect the physical characteristics of the device at different temperatures are established to solve the chip loss and gate resistance. Finally, based on the IGBT finite element thermal model and circuit model, the electro-thermal cosimulation is realized through a control file of Matlab script, the influence of spring failure on the chip switching characteristics is simulated. The results show that the spring failure increases the chip turn-on time and chip loss, impacting the reliability of the device.